Veterinaria Italiana (Journal)
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P7-05 The Seroprevalence of Brucellosis and Molecular Characterization of Brucella Species Circulating Among Pre- Slaughtered Animals and Workers in Slaughterhouses in Amman, Mafraq & Karak Governorates
No full textBrucellosis is a zoonotic disease of occupational nature, and it is endemic in Eastern Mediterranean countries including Jordan. In 2022, we conducted a seroprevalence and molecular study in Jordan among the high-risk occupation of slaughterhouse workers in the central slaughterhouses of three governorates, Amman, Karak and Mafraq, to study brucellosis risk factors and estimate Brucella seropositivity among pre-slaughtered animals and workers. A questionnaire was administered, and blood samples were collected from all workers (356) in the slaughterhouses (Amman n=300, Karak n=22 and Mafraq n=34). Job categories represented in the study included administrative staff, veterinarians, slaughterers and animal skinners, viscera handlers, loaders of live animals, meat sellers, carcass handlers, cleaners, and drivers. The collected samples were tested for Brucella-specific IgM and IgG antibodies using the enzyme-linked immunosorbent assay (ELISA). The positive samples were then tested using polymerase chain reaction (PCR). Anti-Brucella antibodies were detected in 11.8% of the samples. The seroprevalence rate was highest among viscera handlers (15.7%) followed by cleaners (15.6%), and slaughterers (11.7%). About 35.4% reported eating while working, and 19.9% don’t wear any personal protective equipment (PPEs). Moreover, 140 blood sampleswere collected from animals in each slaughterhouse (Amman n=88, Karak n=20 and Mafraq n=32), and serologically tested. Close to 16% were positive by Rose Bengal, and 37% were positive by Fluorescent Polarization Assay. All human and animal samples were negative by PCR. In conclusion, brucellosis is an infection of occupational health importance. The use of PPEs and safer working practices in slaughterhouses should be advocated. This can be done by conducting awareness sessions in endemic countries like Jordan. Regular laboratory testing of brucellosis in animals arriving at slaughterhouses should be conducted
P7-06 Prevalence and risk factors of brucellosis in lactating cow and its public health importance in military dairy farms of Bangladesh
No full textBrucellosis is a great concern for dairy farming globally including in Bangladesh. It is also an important zoonosis having public health significance. The seroprevalence, risk factors, and species of Brucella prevalent in Bangladesh are known to large extent but the military dairy farms are totally unknown. The objective of the current work was to determine the Sero-molecular prevalence, identify risk factors, detect Brucella species, and assess workers’ knowledge, awareness, and practices relevant to the transmission of brucellosis and itspublic health importance in Military Dairy Farms of Bangladesh. Serum and milk samples from 1003 lactating dairy cows of eight military dairy farms and 715 serum samples of dairy farm workers and hospital patients were collected during the 36 months from 2017 to 2020. Five different commercial diagnostic test kits were used to detect the prevalence of Brucella infection for testing all the collected sera and milk samples. Multivariable logistic regressions were used to identify important risk factors for brucellosis. The overall 2.39% seroprevalence of brucellosis was recorded with all the CFT, SAT, and ELISA assays and 3.09% with RBT, whereas only 0.20% of tested milk samples showed positive with MRT in the lactating dairy cows. The result also showed that Out of 715 tested human sera, only 4 (0.5%) milker’s sera were positive for RBT with a 95% confidence interval of 0.2 to 1.5. Brucellosis was also significantly higher in cows that calved more than three times odds ratio [OR] =3.7; (95% confidence interval [CI]: 1.5-9.1) than those calved one to two times. The odds of brucellosis were about 43 times higher (OR = 42.9; (95% confidence interval [CI]: 10.7- 100.107) in aborted cows than in non-aborted cows. This study showed that 55.4% had adequate knowledge about brucellosis as a human disease. Results suggest that B. abortus was endemic and first time identified as human brucellosis in occupationally exposed military dairy farm workers in Bangladesh. The risk factors identified in this study would help to prevent, control, and eradication of brucellosis not only in eight military dairy farms but also in other dairy industries in Bangladesh
O9-2 Brucella ceti infection in cetaceans from Italian Seas: associated lesions and epidemiological data
No full textBrucella ceti infections have been increasingly reported in cetaceans, although a limited characterization of Mediterranean Brucella spp. isolates has been previously reported. We focused on 23 cases of B. ceti infection occurred in striped dolphins stranded along the Italian coastline from 2012 to 2021, investigated by the network of Istituti Zooprofilattici Sperimentali laboratories, coordinated by the National Reference Centre for Diagnostic Investigations on Stranded Marine Mammals (C.Re.Di.Ma.). We assessed the gross and microscopic findings, the results of microbiological, biomolecular and serological investigations, as well as the detection of other relevant pathogens, and the results of whole genomic sequencing and comparative genomic analysis. Pathological changes consistent with B. ceti infection were detected in the central nervous system of 19 animals, showing non-suppurative meningoencephalitis; 5 of which showed B. ceti-associatedpathological findings also in other tissues. In 6 cases severe coinfections were detected, mostly involving Dolphin Morbillivirus (DMV). We classified the 23 isolates into two sequence types, the ST26, prevalent, and the ST49. Whole genome SNP analysis showed that strains from Italy clustered into five genetically distinct clades. Plotting these clades onto the geographic map suggests a link between their phylogeny and topographical distribution (Adriatic Sea, Ionian Sea, Ligurian Sea, Sardinian Sea, Tyrrhenian Sea) alongside a potential indication of separation of the circulating striped dolphins. These results represent an exhaustive characterization of B. ceti isolated from Italian waters and show the usefulness of WGS for understanding of the evolution of this emerging pathogen. The severity of B. ceti-associated lesions reported herein confirms the role of this microbial agent as a primary neurotropic pathogen in striped dolphins, as well as a probable cause of stranding events and death, as previously described. Moreover, our findings highlight the importance of a multidisciplinary approach in the monitoring of stranded cetaceans, with epidemiological data and laboratory informations truly shared across sectors in a One Health-based perspective
P1-01 Genetic diversity of Brucella spp. isolates in Iran: A multilocus sequence typing analysis
No full textBrucellosis is an endemic infection in Iran and causes important economic losses in livestock as well as a serious health problem in humans. The aim of the current study was to evaluate the genetic diversity of Brucella spp. isolated from livestock and human in Iran through the multi locus sequence analysis (MLST). A comprehensive phylogenetic analysis has been achieved to understand the relationship of Brucella genotypes identified in Iran to those originating from different regions across the globe. A total of 30 Brucella isolates were recovered from 8 milk samples collected from cows (n=7) and camels (n=1), human blood samples (n=12), cow lymph nodes (n=4), and 6 aborted fetuses from sheep (n=3), cows (n=2) and goat (n=1). MLST -9 analysis was used to characterize the genetic diversity among B. abortus and B. melitensis isolates. Classical biotyping and molecular identification through AMOS PCR and Bruce-ladder PCR showed that all Brucella isolates were either B. abortus or B. melitensis. B. melitensis was associated with ovine/caprine, camel, cow samples, and the majority of human blood samples (n=12). In contrast, B. abortus was related to bovine samples and a single human sample, indicating that both B. melitensis and B. abortus may contribute to the human brucellosis burden in Iran. B. melitensis isolates comprised 4 MLSA-9 genotypes, the common and globally distributed ST8, ST7, ST71, and ST102. However, four B. melitensis isolates represented a novel ST from human and cow sources. B. abortus isolates belonged to the common MLSA-9 genotypes ST1 and ST2 with relationships to biotype and other PCR-based typing methods. The current results represent the first molecular characterization of Brucella strains circulating in Iran and provide the basis for further studies examining the molecular epidemiology of Brucella spp. in Iran and their relationships to those circulating worldwide
P6-07 The comparison of a fourplex HRM and Taqman qPCR assays for the detection of Brucella spp and Coxiella burnetii in ruminants abortion cases from Botswana
No full textBrucellosis in livestock significantly impacts many countries’ economies, primarily affecting animal health and productivity. It causes direct losses for the animal industry and is a barrier to the international trade of live animals. It is a zoonosis as well, hence affecting public health. A newly developed multiplex high-resolution melt (HRM)real-time (q) polymerase chain reaction (PCR) for simultaneous detection of four abortive zoonotic agents in domestic ruminants was compared with probe-based qPCR assaysto detect Brucella spp. and Coxiella burnetii. Ninety-seven (97) clinical samples from cattle, sheep, and goat abortion cases submitted to Botswana National Veterinary Laboratory from 2010 to 2021 for disease diagnosis, and 34 milk samples submitted to the same laboratory for routine quality control were subjected to fourplex HRM and Taqman assays. The fourplex assay detected Brucella spp. in 13 samples and co-infection of Brucella spp. with Coxiella burnetii in 45 samples.There was a perfect agreement between the HRM assay and each of the two qPCRs (kappa =1). Similarly, the Bland-Altman analysis showed a mean Cq difference of -0.7 for HRM versus Brucella qPCR and 0.63 for HRM versus Coxiella qPCR, suggesting a good agreement. In conclusion, the HRM fourplex assay is a valuable diagnostic tool to detect Brucella species with reliable Cq values com-parable with the Taqman assays
O5-1 Registered Influenza Viral Vector Based Brucella abortus Vaccine for Cattle in Kazakhstan: Age-Wise Safety and Efficacy Studies
No full textVaccination is an effective tool for controlling brucellosis in livestock. A novel influenza viral vector based Brucella abortus vaccine (Flu-BA) was introduced for use in cattle in Kazakhstan in 2019. In this study, the safety and efficacy of the vaccine was evaluated in male and female cattle at different ages, and during pregnancy as a part of its registration process. Our data demonstrated that the Flu-BA vaccine was safeafter prime or booster vaccination in calves (5-7 months old male and female), heifers (15-17 months old) and cows (6-7 years old) and was not abortogenic in pregnant animals. A mild, localized granuloma was observed at the Flu-BA injection site. Vaccinated animals did not show signs of influenza infection or reduced milk production in dairy cows, and the influenza viral vector (IVV) was not recovered from nasal swabs or milk. Vaccinated animals in all age groups demonstrated increased IgG antibody responses against Brucella Omp16 and L7/L12 proteins with calves demonstrating the greatest increase in humoral responses. It does not elicit antibodies that respond positively to routine serologic brucellosis diagnostic tests, and therefore meets the DIVA criterion. Following experimental challenge with B. abortus 544, vaccinates demonstrated greater protection and no signs of clinical disease, including abortion, were observed. The vaccine effectiveness against B. abortus 544 infection was 75, 60 and 60%, respectively, in calves, heifers and adult cows.Brucella were not isolated from calves of vaccinated cattle that were experimentally challenged during pregnancy. Our data suggests that the Flu-BA vaccine is safe and efficacious in cattle, including pregnant animals; and can therefore be administered to cattle of any age
P6-09 Brucellosis in Buffaloes: Serologic Diagnostic
No full textBrucellosis is an endemic disease in many regions of the world. Buffalo herds have been increasing, and it is praised for the elaboration of premium products. Buffaloes are frequently infected by brucellosis and several serological tests have been employed for the detection of this disease. Here we show comparative performance among these serological tests for diagnosis brucellosis in buffaloes. Blood samples were taken from a herd of 50 adult unvaccinated animals, where abortions were reported. Sera were frozen at -20° C until processing. Buffer Plate Antigen (BPAT), Flourescent polarization (FPA) and complement fixation (CFT) were simultaneously performed according to the Manual of Standards for Diagnostics Test and Vaccines (WOAH). FPA was carried out in a SENTRY 100® (Diachemix) fluorescence polarization instrument using a 1/100 serum dilution. CFT was done through micro method, titrating the complement to 50% of hemolysis. The samecut-offs (FPA: 105 mP; CFT: 41 ICFTU (International complement fixation test units) were used as in cattle for the determination of positive and negative animals. 22 samples were positive to BPAT, FPA and CFT. All sera that were positive for BPAT showed strong agglutination. FPA results obtained in the positive sera were in the range between 170 and 250 mP while the average measurement of the negative control was 75 mP. CFT was positive at very high serum dilutions in all confirmed samples. No false positive results for BPAT were obtained in any sample. FPA and CFT confirmed exactly the same results that BPAT anticipated. Serological diagnosis for brucellosis in buffaloes is sometimes controversially. These results suggested that FPA might be used as a confirmatory test for brucellosis in buffalo, due to the same performance relative to CFT, its adjustable cut- off useful in different epidemiological situations, its reliability and ease of performance.CFT is a very useful test, as long as proper equipment and trained laboratory professionals are available. We show here a very precise methodology using BPAT as screening test and FPA as confirmatory one. A larger study is needed in order to obtain a cut-off that responds to the current epidemiological situation of brucellosis in buffaloes
S05 Mapping Global Bushmeat Activities to Improve Zoonotic Spillover Surveillance
No full textHuman populations that hunt, butcher, and sell bushmeat (bushmeat activities) are at increased risk for zoonotic pathogen spillover. Despite associations with global epidemics of severe illnesses, such as Ebola and Mpox, quantitative assessments of bushmeat activities are lacking. However, such assessments could help prioritize pandemic prevention and preparedness efforts.
We used geospatial models that combined published data on bushmeat activities and ecologic and demographic drivers to map the distribution of bushmeat activities in rural regions globally. We stacked the model predictions from Random Forest, Boosted Regression Trees, and Bayesian Additive Regression Trees, and used those as metacovariates for an ensemble model. We used a binomial logistic regression model in a hierarchical Bayesian framework with an intrinsic conditional autoregressive model (iCAR) to assemble the model predictions.
The resulting map had high predictive capacity for bushmeat activities (true skill statistic = 0.94). The model showed that mammal species richness and deforestation were principal drivers of the geographic distribution of bushmeat activities and that countries in West and Central Africa had the highest proportion of land area associated with bushmeat activities
These findings could help prioritize future surveillance of bushmeat activities and forecast emerging zoonoses at a global scale
P04.3 Spatial and temporal analysis on the impact of ultra-low volume indoor insecticide spraying on Aedes aegypti household density
No full textAedes aegypti is the primary vector for several arboviruses that can cause widespread epidemics, such as Dengue and Zika. This mosquito feeds primarily and frequently on humans, and is well adapted to the urban environment, where it has successfully established itself in many areas throughout the tropics and subtropics. Ultra-low volume (ULV) indoor insecticide spraying has been shown to be effective at reducing Ae. aegypti density for short periods of time (Gunning et al., 2018), however the spatial extent of the vector control effect along the margins of a treated area is unclear, as is the potentially reduced effect of incomplete spray coverage within the treated area. In this study, we characterize the impact of pyrethroid ULV indoor spraying on the Ae. aegypti population within households in relation to the spray events occurring in the proximity of that household in time and space. Improved understanding of the duration and the distance of the effect of a spray intervention on Ae. aegypti populations can better inform planning the coverage and frequency of sprays needed during vector control interventions, as well as modeling efforts that contrast different vector control strategies.
This project uses data from two large-scale experiments that involved six cycles of indoor pyrethroid spray applications in the Amazonian city of Iquitos, Peru (Gunning et al. 2018). We developed spatial multi-level models to disentangle the reduction in Ae. aegypti numbers that resulted from (1) recent ULV treatment of a specific household and (2) ULV treatment of households in the neighboring area. We compared the fit of models including different weighting schemes for the spray effect, based on different temporal and spatial decay functions to understand lagged ULV effects.
Our results suggest that the effect of a spray event in a house wanes over time following a gaussian decay, with a spray that occurred between 9-30 days ago having half the effect of a spray that occurred the day before. In addition, we found that the reduction of Ae. aegypti density is mainly determined by time since the most recent spray event, with no significant explanatory value added by the cumulative effect of multiple past sprays. Our results also indicate that the reduction of the Ae. aegypti in a house is due to spray events occurring in that same house, with no significant effect of sprays occurring in adjacent houses or the neighboring area. In summary, the reduction of Ae. aegypti in a house is determined mainly by the time since the last spray intervention in that same house. Together, our results suggest that increased coverage rather than increased frequency of sprays should be the priority of indoor vector control programs
R06.4 Spatial analysis to inform African Swine Fever spread modelling in Laos
No full textAfrican Swine Fever (ASF) was first reported in Laos in June 2019, when an incursion caused 150 village outbreaks across all Provinces and territories. Despite stamping out control measures, ASF virus (ASFV) spread rapidly. Understanding the rate of disease spread and the infectious period of ASFV at the village level is necessary to accurately model this disease in the smallholder system which exists in countries such as Laos. However, such parameter estimates are scarce. The aim of this study was to estimate key epidemiologic parameters to enable modelling of ASFV spread in Laos.
Data were collected on ASF outbreaks reported and confirmed via PCR testing during the period 1 June 2019 to 1 January 2020. Information included outbreak date or date of first report, and village location. The latter was used to determine latitude and longitude coordinates.
To estimate disease spread parameters, the Approximate Bayesian Computation Sequential Monte Carlo (ABC-SMC) technique was used to validate simulated disease parameters against the reported ASF outbreaks using a compartmental disease model. A prior for between-village transmission was based on ASFV outbreaks between smallholder farms in Uganda, represented as a gamma distribution. For the latent (mean, shape) and mean infectious periods, various estimates based on experimental and field studies from published studies were used.
A critical assumption is homogenous mixing within the modeled population. To better meet this assumption, the outbreak data were analysed to identify likely spatiotemporal clusters; these clusters were assumed to represent the occurrence of linked, village spread of ASFV.
The final dataset contained 150 outbreak villages representing all Provinces in Laos. Six spatiotemporal clusters were identified. The size of these clusters ranged from 4 to 14 case villages, radii 16 to 153km and period 0 to 22 days.
The mean estimated latent period was 5.82 to 5.95 days across the clusters, the mean village infectious period 61.53 to 67.70 days, and mean β 0.19 to 0.51. The R0 ranged from 13.06 to 31.06 across the clusters. Simulated outbreaks utilising the estimated transmission parameters struggled to match the observed data in clusters in which fewer than ten outbreaks occurred or where all outbreaks were reported over only one to two days.
Spatio-temporal analysis can be used to improve ASFV transmission parameter estimation, thus improving outputs from disease spread models. However, this study demonstrates that the value provided by such approaches can be limited by the surveillance data that is available